Avalanche Advisory

ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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The Bottom Line

The avalanche hazard is MODERATE today above and below treeline. It will be possible for snowmachiners, skiers and snowboarders to trigger wind slabs 1-3’ in depth that formed yesterday on a variety of aspects and elevations. A layer of weak snow deeper in the snowpack also has the potential to release slabs anywhere from 2-4’ in depth in steep terrain.

Avoiding wind loaded features and steep terrain are your best bets for staying out of trouble today.

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale

Avalanche danger is determined by the likelihood, size and distribution of avalanches.

Danger Level

Travel Advice

Likelihood of Avalanches

Avalanche Size and Distribution

5 Extreme

Avoid all avalanche terrain.

Natural and human- triggered avalanches certain.

Large to very large avalanches in many areas.

4 High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human- triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

Thank you to all of our supporters! Observations, feedback and community input help us to make the CNFAIC an effective and valuable resource for everyone. Another way to help support the avalanche center is by donating to the Friends of the CNFAIC. This can be done through Pick.Click.Give or directly to the F-CNFAIC. Every little bit helps. Thanks!

Avalanche Problem 1

Strong and gusty winds created very sensitive wind slabs during the day yesterday (see video & observation HERE). An ample amount of light density snow was moved easily by these winds and formed slabs 2-3 feet thick. We received one report of a snowmachine triggered avalanche in one of these wind loaded areas yesterday. details HERE. Natural and human triggered avalanche activity was observed and reported by multiple parties over the weekend.

Snowmachine triggered avalanche in a wind loaded starting zone in Triangle Bowl. No one was injured or buried. (Photo: Kolin Smith)

Today expect the sensitivity of these slabs to be on the decline. It will still be possible to trigger slabs in many areas, as the winds affected slopes above and below treeline yesterday. It’s important to learn how to recognize wind slabs. Gullies that have been cross loaded, cornices and wind lips at the top of slopes, and any snow that has a smooth, rounded or pillowy look to it are worth avoiding today.

Avalanche Problem 2

Weak faceted snow that is sitting between the late January crust and the snow that has fallen in February continues to hold the potential for deeper slabs to release. This layer has been slowly gaining strength but still warrants your attention. Combine this problem in areas where newly formed wind slabs are up to 3 feet on their own and the consequences (volume and depth of debris) are potentially unsurvivable.

Choosing lower angled terrain, <35 degrees, is the simplest way to avoid triggering slabs up to 3’ in depth. Avoiding spots where slab depth quickly changes from thin to thick (i.e. starting zones, cross loaded gullies) will also help in avoiding trouble today.

Mountain Weather

The most significant weather factor contributing to instability over the last 24 hours was wind. Wind data from ridgetop stations were the following:Sunburst- 13 avg - 55 gust out of the EastSeattle- 22 avg - 53 gust out of the SouthFresno- 18 avg - 40 gust out of the North

Temperatures over the last 24 hours averaged 17 degrees F at the Sunburst weather station. It has been 6 days since the last precipitation has fallen.

Today expect sunny skies. Winds speeds will remain elevated, averaging in the 20-30mph range out of the Southeast. Temperatures at 1,000’ will be in the high 20s to low 30s F

A ridge of high pressure over most of Alaska is preventing moisture from reaching our area. There is a slight chance for some light precipitation tomorrow, but much of that depends on the ability of that high pressure ridge to prevent low pressure from the south and west to move over us. The rest of the week looks to be dry and clear with slightly warming temperatures as high pressure will continue to dominate.

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Dec 18, 2018 )

AREA

STATUS

WEATHER AND RIDING CONDITIONS

Glacier District

Johnson Pass:

Open

Please stay on trail to avoid resource damage through Forested areas.

Placer River:

Closed

Closed

Skookum Drainage:

Closed

Closed

Turnagain Pass:

Closed

Closed November 21 due to inadequate snow conditions. #hopeforsnow

Twentymile:

Closed

Closed

Seward District

Carter Lake:

Open

Lost Lake Trail:

Open

Please stay on trail to avoid resource damage through Forested areas.

Primrose Trail:

Open

Please stay on trail to avoid resource damage through Forested areas.

Resurrection Pass Trail:

Closed

Closed for the 2018/19 season. Next season will be open to motorized use.

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.